A loaded question for someone in the education business:
Have you ever had a bad teacher? In what way was s/he bad?
Yes; she was a racist and a bigot and she taught high school history with those flavors.
At a New England boarding school, I had a teacher who told me I would never aspire to anything more than being an auto mechanic. Turns out he had a master’s degree while I went on and got a Ph.D. Put that in your carburetor and suck on it. (By the way, being a mechanic requires a great deal of skill and expertise. You could do a lot worse.)